Catheters are used in a wide variety of minimally-invasive or percutaneous medical procedures. Balloon catheters having drug coatings may be used to treat diseased portions of blood vessels. Typically, the balloon is inserted through a peripheral blood vessel and then guided via a catheter through the vascular system to the target intravascular site. However, as the balloon travels through the vascular system, the flow of blood may wash away some of the drug coating. In addition, the control of the timing, location, and/or duration of the drug release can be an issue. Therefore, there is a need for improved catheter-based devices for drug delivery to an intravascular site.